CMOS current-mode analog circuit building blocks for RF dc-dc converter controllers

Conventional switch-mode dc-dc converters are operated at frequencies in the order of hundreds of kHz to single MHz. Switching frequencies in the order of tens of MHz would enable applications of RF converters in low power communications and computing integrated circuits with dynamic voltage scaling. Controllers for these converters would have to operate with a bandwidth in the GHz range. The maximum bandwidth for DSP controllers is around 100 MHz. It is expected that current-mode analog signal processing can achieve high enough bandwidths to control RF converters. Two fundamental building blocks for current mode analog integrated circuits are the current conveyor and the current comparator. This paper presents a high-speed current conveyor and current comparator that can be used to implement a feedback VLSI controller for RF dc-dc converters. Simulation results for both circuits show very high speed, low power consumption and small dc offset.